Power tool

ABSTRACT

It is an object of the invention to provide an improvement of the operability in a driving operation using a power tool. A representative power tool may comprise a driving material driven into a workpiece, a driving mechanism to drive the driving material into the workpiece, a motor, an operating device that controls energization and de-energization of the motor including a trigger switch and an internal switch, wherein the operating device further comprising a first mode in which, when the trigger switch is depressed, the internal switch is interlocked with the depressing operation of the trigger switch to be turned to the on-position and held in the on-position, while the trigger switch is returned to the off-position when the trigger switch is released and a second mode in which, when the depressing operation of the trigger switch is continued, the trigger switch is held in the on-position, and the internal switch is released from interlock with the trigger switch and is held in the on-position for a predetermined period of time in the working stroke and then returned to the off-position, while the trigger switch is returned to the off-position when the trigger switch is released.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power tool that performs a strikingoperation of driving materials to a workpiece by linearly moving adriving mechanism.

2. Description of the Related Art

Japanese Utility Model Publication No. 2567867 discloses an actuatingdevice (operating device) of a staple driving (striking) machine whichutilizes a spring force of a coil spring as a driving force for thedriving movement of a driving member in the form of a driver. The knownactuating device includes a contact detection arm that is pressedagainst a workpiece during staple driving operation, a trigger that isdepressed by a user's finger, a lever mechanism comprising a pluralityof levers that arc actuated by the contact detection arm or the triggerand are coordinated with each other or released from the coordination,and a power switch that is turned on and off by the lever mechanism.When tie contact detection arm is pressed against the workpiece and thetrigger is depressed, the power switch is turned on via the levermechanism and the motor is energized. When the motor is energized, thedriver drives in a staple: In the process in which the driver movestoward the initial position after driving movement, the driver returnsthe power switch from the on position to the off position via the levermechanism.

In the known acing device this constructed, each time the trigger isdepressed once, the driver performs one driving operation and thenstopped in the initial position. However, the known actuating device isestablished by the operation of pressing the contact detection armagainst the workpiece and by the operation of depressing the trigger bythe users finger. Therefore, further improvement is desired in theoperability.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide an improvementof the operability in a driving operation using a power tool.

According to the present invention, a representative power tool mayinclude a driving material that is strikingly driven into a workpiece, adriving mechanism that drives the driving material into the workpiece bya linear movement, a motor that actuates the driving mechanism, and anoperating device that controls energization and de-energization of themotor. A working stroke of the driving member is defined as a period oftime from when the driving member starts driving in one driving materialtill when preparing for driving in the next driving material iscompleted. The “power tool” in this invention typically corresponds to anailing machine or a tucker. The “driving material” in this inventionwidely includes a straight rod-like material having

The operating device includes a trigger switch that is normally biasedinto an off position (turning-off position) to disable the driving motorfrom being energized and is turned to an on position (turning-onposition) to enable the driving motor to be energized when the triggerswitch is depressed by the user. Further, the operating device includesan internal switch that is normally biased into an off position(turning-off position) to disable the driving motor from being energizedand is turned to an on position (turning-on position) to enable thedriving motor to be energized by interlocking with the depressingoperation of the trigger switch. The internal switch is held in the onposition for a predetermined period of time in the working stroke andthen returned to the off position. The motor is energized when both thetrigger switch and the internal switch are turned to the on position,while the motor is de-energized when either one of the switches isreturned to the off position. Specifically, when the user depresses thetrigger switch, the motor is energized and a driving member performs anoperation of driving in a driving material.

The operating device has a first mode and a second mode. In the firstmode, when the trigger switch is depressed, the trigger switch is turnedto the on position and the internal switch is interlocked with thedepressing operation of the trigger switch to be turned to the onposition and held in the on position, while the trigger switch isreturned to the off position when the trigger switch is released. In thesecond mode, when the depressing operation of the trigger switch iscontinued, the trigger switch is held in the on position, and theinternal switch is released from the interlock with the trigger switchand is held in the on position for a predetermined period of time in theworking stroke and then returned to the off position, while the triggerswitch is returned to the off position when the trigger switch isreleased. The working stroke of the driving member is started when theoperating device is put into the first mode by the depressing operationof the trigger switch, and after a predetermined time of period elapsesafter start of the working stroke, the operating device switches fromthe first mode to the second mode.

The operating device is put into the first mode when the trigger switchis depressed by the user. Specifically, the trigger switch is turned tothe on position to allow the motor to be energize and the internalswitch is also turned to the on position to allow the driving motor tobe energized by interlocking with the depressing operation of thetrigger switch and then held in the on position. As a result, he motoris energized and the working stroke of driving in a driving material bya driving member is started, and after a predetermined time of periodelapses after start of the working stroke, the operating device switchesfrom the first mode to the second mode. By such switching from the firstmode to the second mode, the trigger switch is held in the on position,while the internal switch is released from the interlock with thetrigger switch and is held in the on position for a predetermined periodof time in the working stroke and then returned to the off position. Asa result, the motor is de-energized. Thus, according to this invention,each time the trigger switch is depressed once, the driving member iscaused to perform one driving operation and then stopped. Such movementcan be reliably performed only by depressing the trigger switch.Specifically, even during the continued depressing operation of thetrigger switch, double driving of the driving member can be reliablyprevented. Therefore, compared with the prior art which requires anoperation of pressing a contact detection arm against a work-piece andan operation of depressing a trigger, the operability of the operatingdevice can be enhanced.

Further, when the depressing operation of the trigger switch isdiscontinued halfway through the working stroke of driving in a drivingmaterial by a driving member, or when the trigger switch is releasedhalfway through the depressing operation, the trigger switch is returnedto the off position. Thus, the motor is de-energized, and the drivingoperation can be stopped in progress. Further, after such interruption,when the trigger switch is depressed again, the driving motor isenergized. Therefore, the once interrupted driving operation of thedriving member can be resumed without any problem.

Other objects, features and advantages of the present invention will bereadily understood after reading the following detailed descriptiontogether with the accompanying drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view, schematically showing an entirebattery-powered pin tucker 100 according to an embodiment of theinvention.

FIG. 2 is a sectional view taken along line A-A in FIG. 1.

FIG. 3 is an enlarged sectional view of an essential part of the pintucker 100.

FIG. 4 is a plan view showing an operating device, in an initial statein which a trigger is not yet depressed.

FIG. 5 is a front view showing the operating device, in the initialstate in which the trigger is not yet depressed.

FIG. 6 is a plan view showing the operating device, in a state in whichthe depressing operation of the trigger is started.

FIG. 7 is a front view showing the operating device, in the state inwhich the depressing operation of the trigger is started.

FIG. 8 is a plan view showing the operating device, in a state in whichthe trigger is further depressed and a cam disc is allowed to rotate.

FIG. 9 is a front view showing the operating device, in the state inwhich the trigger is further depressed and the cam disc is allowed torotate.

FIG. 10 is a plan view showing the operating device, in a state in whichthe trigger is ether depressed and rotation of the cam disc is started.

FIG. 11 is a front view showing the operating device, in the sa in whichthe trigger is further depressed and rotation of the cam disc is start.

FIG. 12 is a plan view showing the opening device, in a state in whichthe trigger is further depressed down to the depressing end.

FIG. 13 is a front view showing the operating device, in the state inwhich the trigger is further depressed down to the depressing end.

FIG. 14 is a plan view showing the operating device, in a state in whichinterlock between the trigger and the cam block is released.

FIG. 15 is a front view showing the operating device, in the state inwhich interlock between the trigger and the cam block is released.

FIG. 16 is a plan view showing the operating device, in a state in whichthe cam block is placed in a position to hold a second switch in theon-position.

FIG. 17 is a front view showing the operating device, in the state inwhich the cam block is placed in a position to hold the second switch inthe on position.

FIG. 18 is a plan view showing the operating device, in a state in whichthe cam block is placed in a position to turn off the second switch.

FIG. 19 is a front view showing the operating device, in the state inwhich the second switch is returned to the off position.

FIG. 20 is a plan view showing the operating device, in a state in whichthe swing arm moves in an attempt to return to the initial, interlockedposition.

FIG. 21 is a front view showing the operating device, in a state inwhich the swing arm moves in an attempt to return to the initial,interlocked position.

FIG. 22 is a perspective view showing the operating device, in a statein which the trigger is not yet depressed.

FIG. 23 is a perspective view showing the operating device, in the statein which the depressing operation of the trigger is started.

FIG. 24 is a perspective view showing the operating device, in the statein which the trigger is further depressed and the cam disc is allowed torotate.

FIG. 25 is a perspective view showing the operating device, in the statein which the trigger is further depressed and rotation of the cam discis started.

FIG. 26 is a perspective view showing the operating device, in the statein which the trigger is further depressed down to the depressing end.

FIG. 27 is a perspective view showing the operating device, in the statein which interlock between the trigger and the cam block is released.

FIG. 28 is a perspective view showing the operating device, in the statein which the cam block is placed in a position to hold the second switchin the on position.

FIG. 29 is a perspective view showing the operating device, in the statein which the second switch is returned to the off position.

FIG. 30 is a perspective view showing the operating device, in the statein which the swing arm moves in an attempt to return to the initial,interlocked position.

FIG. 31 is a plan view showing the swing arm.

FIG. 32 is a perspective view showing the swing arm.

FIG. 33 is a sectional view taken along line A-A in FIG. 1, in the statein which the hammer 125 is in a driving standby position.

FIG. 34 shows a ratchet wheel 116 and a leaf spring 118 forming areverse rotation preventing mechanism of a speed reducing mechanism 115in this embodiment, as viewed from the side of a driving mechanism 117in FIG. 3.

FIG. 35 is a side view of the ratchet wheel 116 and the leaf spring 18shown in FIG. 5.

FIG. 36 shows an operating device 160 for controlling energization andde-energization of a driving motor 113 according to this embodiment.

FIG. 37 shows a reverse rotation preventing mechanism in the state inwhich an end 171 a of a cam block 171 is butted against a stoppersurface 178 d of a cam disc 177 after completion of the working strokeof the driving operation.

FIG. 38 shows the reverse rotation preventing mechanism is in the statein which the end 171 a of the cam block 171 is disengaged from thestopper surface 178 d of the cam disc 177.

DETAILED DESCRIPTION OF THE INVENTION

Each of the additional features and method steps disclosed above andbelow may be Utilized separately or in conjunction with other featuresand method steps to provide and manufacture improved power tools andmethod for using such power tools and devices utilized therein.Representative examples of the present invention, which examplesutilized many of these additional features and method steps inconjunction, will now be described in detail with reference to thedrawings. This detailed description is merely intended to teach a personskilled in the art further details for practicing preferred aspects ofthe present teachings and is not intended to limit the scope of theinvention. Only the claims define the scope of the claimed invention.Therefore, combinations of features and steps disclosed within thefollowing detailed description may not be necessary to practice theinvention in the broadest sense, and are instead taught merely toparticularly describe some representative examples of the invention,which detailed description will now be given with reference to theaccompanying drawings.

A representative embodiment of the present invention will now bedescribed with reference to FIGS. 1 to 5. FIG. 1 is a sectional sideview, schematically showing an entire battery-powered pin tucker 100 asa representative example of a power tool according to the embodiment ofthe present invention. FIG. 2 is a sectional view taken along line A-Ain FIG. 1. FIG. 3 is an enlarged sectional view of an essential part ofthe pin tucker 100. As shown in FIG. 1, the pin tucker 100 of thisembodiment includes a body 101, a battery case 109 tat houses a battery,and a magazine 111 that is loaded with driving materials in the form ofpins to be driven into a workpiece.

The body 101 includes a motor housing 103 that houses a driving motor113, a gear housing 105 that houses a driving mechanism 117 and a hammerdrive mechanism 119, and a handgrip 107 that is held by a user. Thehandgrip 107 is disposed above the motor housing 103. The gear housing105 is disposed on one horizontal end (on the right side as viewed inFIG. 1) of the motor housing 103 and the handgrip 107, and the batterycase 109 is disposed on the other horizontal end thereof. The magazine111 is designed to feed pins to be driven to the lower end of the gearhousing 105 or to a pin injection part 112 connected to the end of thebody 101.

As shown in FIG. 3, the driving mechanism 117 includes a rod-like slideguide 121, a hammer 125, a compression coil spring 127 and a driver 129.The slide guide 121 vertically linearly extends and its upper and lowerends are secured to the gear housing 105. The hammer 125 is verticallymovably fitted onto the slide guide 121 via a cylindrical slider 123.The compression coil spring 127 exerts a spring force on the hammer 125to cause downward driving movement of the hammer 125. The driver 129 ismoved together with the hammer 125 and applies a striking force to a pinfed to a pin driving port 112 a of the injection part 112. The driver129 is a feature that corresponds to the “driving member” according tothe present invention. The driver 129 is connected to the hammer 125 bya connecting pin 131. Further, the hammer 125 has upper and lowerengagement projections 125 a, 125 b that are lifted up by engagementwith upper and lower lift rollers 137, 139. The pin and the workpieceare not shown in the drawings.

The compression coil spring 127 in this embodiment is configured tobuild up the spring force by compression and release the built-up springforce by freely extending. The compression coil wring 127 is a featurethat corresponds to the “coil spring” according to this invention. Thedriver 129 is connected to the hammer 125 by the connecting pin 131.Further, the hammer 125 has an upper engagement projection (theengagement projection 125 a shown in FIGS. 2 and 3) and a lowerengagement projection (the engagement projection 125 b shown in FIG. 2).The upper engagement projection 125 a is lifted up by engagement with anupper lift roller (the lift roller 137 shown in FIG. 2). The lowerengagement projection 125 b is lifted up by engagement with a lower liftroller (the lift roller 139 shown in FIGS. 2 and 3). The pin as adriving material comprises a straight rod-like material having a pointedend with or without a head,

Further, a safety lever 143 for disabling the depressing operation ofthe trigger 141 is provided on the handgrip 107. The depressingoperation of the trigger 141 is disabled when the safety lever 143 isplaced in a locked position shown by a solid line in FIG. 1, while thedepressing operation is enabled when the safety lever 143 is placed in alock released position shown by a phantom line in FIG. 1. Further, alight 145 (see FIG. 1) for illuminating a pin driving region is providedon the body 101. A light illuminating switch 147 is turned on by thesafety lever 143. When the safety lever 143 is placed in the lockedposition, the switch 147 is turned off so that the light 145 goes out.

The rotating output of the driving motor 113 is transmitted to thehammer drive mechanism 119 via a planetary-gear type speed reducingmechanism 115. As shown in FIGS. 2 and 3, the hammer drive mechanism 119includes upper and lower gears 133, 135 that rotate in oppositedirections in a vertical plane in engagement with each other, and theupper and lower lift rollers 137, 139 (see FIG. 2) that lift up thehammer 125 by rotation of the gears 133, 135.

The gears 133, 135 are rotatably mounted on a frame 134 disposed withinthe gear housing 105, via shafts 133 a, 135 a The lift rollers 137, 139are rotatably mounted to the gears 133, 135 via support shafts 137 a,139 a in a position displaced from the center of rotation of the gears133, 135. When the gears 133, 135 rotate, the lift rollers 137, 139revolve around the center of rotation of the gears 133, 135 along anarc. The amount of displacement of the support shaft 137 a of the upperlift roller 137 is equal to the amount of displacement of the supportshaft 139 a of the lower lift roller 139. The lower gear 135 engageswith a driving gear 115 b formed on an output shaft 115 a of the speedreducing mechanism 115 and is rotated in a predetermined reduction gearratio. The gear ratio of the lower gear 135 to the upper gear 133 standsat one to one. Further, the upper and lower lift rollers 137, 139 aredisposed with a phase difference of approximately 180°. The initialposition of the upper and lower lift rollers 137, 139 is defined here asthe state in which the lift rollers 137, 139 are in the remotestposition from each other, or in which the lower lift roller 139 islocated on the lower side of the lower gear 135 and the upper liftroller 137 is located on the upper side of the upper gear 133 (as shownin FIG. 2).

When the driving motor 113 is energized and the upper and lower gears133, 135 are caused to rotate in the direction of the arrow in FIG. 2,the lower lift roller 139 engages from below with the lower engagementprojection 125 b of the hammer 125 located at the bottom dead center andmoves upward along an arc, and thereby lifts up the hammer 125 byvertical components of the circular arc movement. When the amount oflift of the hammer 125 by the lower lift roller 137 reaches near themaximum the upper lift roller 137 in turn engages from below with theupper engagement projection 125 a of the hammer 125 and moves upwardalong an arc, and thereby lifts up the hammer 125. In this manner, thehammer 125 is moved upward from the bottom dead center (the position ofcompletion of pin driving, or the initial position) toward the top deadcenter via the relay of the upper and lower lift rollers 137, 139. Thecompression coil spring 127 is compressed by this upward movement of thehammer 125 and builds up the spring force. The upper engagementprojection 125 a of the hammer 125 is further passed over from the upperlift roller 137 to a cam 140 in the region of the top dead center. Whenthe driver 129 is lifted upward together with the hammer 125, a pin inthe magazine 111 is fed to the pin injection port 112 a of the injectionpart 112. Thereafter, upon disengagement from the cam 140, the hammer125 is caused to perform a downward driving movement by the spring forceof the compression coil spring 127. Thus, the pin fed to the pininjection port 112 a of the injection part 112 is driven into theworkpiece by the driver 129 moving downward through the pin injectionport 112 a. After completion of the driving movement, the hammer 125 isheld at the bottom dead center by contact with a stopper 126.

After disengagement of the cam 140 and the hammer 125, in order toprepare for the next hammer lifting movement, the gears 133, 135continue to further rotate until they return to and stop at the initialposition in which the upper and lower lift rollers 137, 139 are remotestfrom each other. Specifically, the period of time from when the lowerlift roller 139 is driven and starts upward lifting movement of thehammer 125 together with the driver 129 in engagement with the hammer125 till when the lower lift roller 139 returns to the initial positionand prepares for the next hammer lifting movement, corresponds to the“working stroke” according to this invention and represents one turn ofeach of the gears 133, 135.

An operating device 160 for controlling energization and de-energizationof the driving motor 113 will now be described in detail with referenceto FIGS. 4 to 32. First, the construction of the operating device 160will be described with reference to FIGS. 4, 5 and 22. The operatingdevice 160 includes a trigger switch 163 that is turned on by depressingoperation of the user, an internal switch 161 that is turned on byinterlocking with the depressing operation of the trigger switch 163,and a cam disc 177 that controls a subsequent once or off-state of theon-state internal switch 161. The cam disc 177 is a feature thatcorresponds to the “control member” according to this invention.

The trigger switch 163 is arranged on the handgrip 107 and includes atrigger 141 that is linearly depressed by the user, a lost switch 148(see FIGS. 1 and 3) and a swing arm 164. The first switch 148 isnormally biased by a biasing spring (not shown) into the off position todisable the driving motor 113 from being energized. When the trigger 141is depressed, the first switch 148 is turned to the on position toenable the driving motor 113 to be energized. The swing arm 164interlocks the depressing operation of the trigger 141 to the internalswitch 161, The trigger 141 and the swing arm 164 are features thatcorrespond to the “finger operating member” and the “interlockingmember”, respectively, according to this invention. The trigger 141 islinearly movably mounted to a guide plate 168 fixedly mounted to a frame134. The trigger 141 is biased by a compression coil spring 165 in adirection opposite to the depressing direction and is normally held in apre-operational or released position. When the trigger 141 is depressed,the first switch 148 is turned on via a lever 163 b (see FIG. 3). Theswing arm 164 is connected to the trigger 141 via a shaft 163 a and canrotate in a direction crossing the depressing direction of the trigger141. When the trigger 141 is depressed, the swing arm 164 is switchedbetween an interlocked position (shown in FIG. 5) in which it isinterlocked with a cam block 171 of the internal switch 161 which willbe described below and a interlock released position (shown in FIG. 15)in which such interlock is released. The interlocked position and theinterlock released position correspond to the “operating position” andthe “non-operating position”, respectively, according to this invention

The internal switch 161 includes the cam block 171 that linearly movesby interlocking with the depressing operation of the trigger 141, aswitch arm 172 that is rotated by the cam block 171, and a second switch173. The second switch 173 is normally biased by a biasing spring (notshown) into the off position to disable the driving motor 113 from beingenergized. When the switch arm 172 is rotated, the second switch 173 isturned to the on position to enable the driving motor 113 to beenergized. The cam block 171 is a feature that corresponds to the“operating member” according to this invention. The cam block 171 ismounted to the frame 134 such that the cam block 171 can linearly movein the same direction as the depressing direction of the trigger 141.The cam block 171 has an engagement portion 171 a that faces the swingarm 164 located in the interlocked position. When the trigger 141 isdepressed, the swing arm 164 moves in the depressing direction togetherwith the trigger 141 and an end surface 164 a of the swing arm 164 comesinto surface contact with the engagement portion 171 a The engagementportion 171 a is then pushed in a surface contacting manner.Specifically, the cam block 171 is caused to move linearly byinterlocking with the depressing operation of the trigger 141 and pushesone end of the switch arm 172 via a push pin 174. Thus, the switch arm172 swings on a shaft 172 a and turns on the second switch 173. Theswitch arm 172 is biased by a first torsion spring 175 in the directionof turning off the second switch 173.

Further, a second torsion spring 166 is provided on the swing arm 164(see FIGS. 31 and 32), and a third torsion spring 167 is provided on thetrigger 141. The second torsion spring 166 corresponds to the “elasticmember” and the “second spring member” and the third torsion spring 167corresponds to the “fist spring member” according to this invention. Thesecond torsion spring 166 has one leg 166 a engaged with the swing arm164 and the other leg 166 b held free. When the free leg 166 b isrotated on the shaft 163 a, the swing an 164 is rotated via the secondtorsion spring 166. The end of the free leg 166 b of the second torsionspring 166 is bent about 90°. The third torsion spring 167 has one leg167 a engaged with the trigger 141 and the other leg 167 b engaged withthe free leg 166 b (the bent portion) of the second torsion spring 166.Thus, the biasing force of the third torsion spring 167 is normallyapplied in a direction that rotates the swing arm 164 from theinterlocked position to the interlock released position via the secondtorsion spring 166. This biasing force is received by the guide plate168.

The guide plate 168 has a guide surface 169 that is engaged with thefree leg 166 b of the second torsion spring 166. The guide surface 169includes a flat surface portion 169 a and an inclined surface portion169 b. The flat surface portion 169 a extends in a direction parallel tothe direction of operation of the trigger 141 or the direction ofmovement of the cam block 171. The inclined surface portion 169 bcontiguously extends from the flat surface portion 169 a. When thetrigger 141 is in the released position, the flat surface portion 169 areceives the free leg 166 b of the second torsion spring 166, so thatthe swing arm 164 is held in the interlocked position. The guide plate168 corresponds to the “guide member” according to this invention. Whenthe trigger 141 is depressed, the swing arm 164 moves together with thetrigger 141 and the end surface 164 a of the swing arm 164 comes intosurface contact with the engagement portion 171 a of the cam block 171.Thus, the swing arm 164 is pushed in the direction that turns on thesecond switch 173. By this movement, the free leg 166 b of the secondtorsion spring 166 passes over the flat surface portion 169 a of theguide surface 169 and moves onto the inclined surface portion l 69 b. Atthis time, the swing arm 164 is held in the interlocked position againstthe biasing force of the third torsion spring 167 by the frictionalforce of the contact surfaces between the swing arm 164 and the camblock 171. Therefore, the free leg 166 b of the second torsion spring166 is located in a position (space) in which the free leg 166 b isdisengaged from the inclined surface 169 b (see FIG. 9). Thereafter, thecam block 171 is further moved in a throwing direction (triggerdepressing direction) that turns on the second switch 173 by the camdisc which will be described below. The swing arm 164 is then disengagedfrom the cam block 171. At this time, the Swing arm 164 is rotated fromthe interlocked position to the interlock released position by thebiasing force of the third torsion spring cam 167 (see FIG. 15).

When the trigger 141 is released and returned to the released position,the swing arm 164 in the interlock released position is returned to theinitial position or the interlocked position after passing underneaththe cam block 171 if the cam block 171 is returned to the initialposition earlier than the trigger 141, which will be described below.

As mentioned above, in the operating device 160 according to thisembodiment, when the trigger 141 is depressed, the cam block 171 isinterlocked with the trigger 141 via the swing arm 164, so that thefirst switch 148 is turned on by the trigger 141. At the same time, thesecond switch 173 is turned on via the cam block 171, the push pin 174and the switch arm 172. When both the first and second switches 148 and173 are turned on, the motor is energized, while either one of the firstand second switches 148 and 173 is turned off, the motor isde-energized. The first and second switches 148 and 173 are disposed inalignment with each other as seen in FIGS. 1 and 3. Therefore, thesecond switch 173 is not shown in FIGS. 1 and 3.

Next, the cam disc 177 for controlling the cam block 171 will now bedescribed with reference to FIGS. 4 and 22. The cam disc 177 is mountedin such a manner as to rotate together with the upper gear 133 of theabove-described hammer drive mechanism 119 (see FIG. 3). The cam disc177 has a circumferential surface designed as a cam face 178 and isdisposed such that the end of the cam block 171 faces the cam face 178.The cam face 178 of the cam disc 177 includes a rake region 178 a, alarge-diameter region 178 b and a small-diameter region 178 c in thecircumferential direction. When the trigger 141 is depressed and the camblock 171 is moved in the throwing direction that turns on the secondswitch 173, the rake region 178 a engages with the end of the cam block171. The rake region 178 a then further moves the cam block 171 in thethrowing direction and thereby releases the interlock between the camblock 171 and the swing arm 164. The large-diameter region 178 b moveswhile being held in engagement with the end of the cam block 171 andthereby holds the second switch 173 in the on position. Thesmall-diameter region 178 c disengages from the end of the cam block 171and allows the second switch 173 to be returned to the off position. Therake region 178 a, the large-diameter region 178 b and thesmall-diameter region 178 c are features that correspond to the“interlock released region”, the “on-state continuation region” and the“off-state return region”, respectively, according to this invention.

In order to avoid excessive movement of the switch arm 172 when the camblock 171 is further moved in the throwing direction by the rake region178 a, the push pin 174 disposed between the cam block 171 and theswitch arm 172 is designed to be movable in the same direction as theOwing direction with respect to the cam block 171. Further, the push pin174 is held in contact with the switch arm 172 by the biasing force of abiasing spring 174 a Specifically, when the cam block 171 is moved inthe throwing direction by the rake region 178 a, the push pin 174absorbs the movement of the cam block 171 by moving with respect to thecam block 171.

The rake region 178 a is provided between the large-diameter region 178b and the small-diameter region 178 c and comprises an inclined surfaceextending linearly from the small-diameter region 178 c to thelarge-diameter region 178 b. The large-diameter region 178 b and thesmall-diameter region 178 c each comprise a surface of a circular arcshape defined on the axis of rotation of the cam disc 177. Further, thecam disc 177 has a stopper surface 178 d on the boundary between thesmall diameter region 178 c and the rake region 178 a The stoppersurface 178 d contacts the side surface of the end of the cam block 171and thereby prevents the cain disc 177 from rotating beyond a specifiedposition (overrunning). The initial position of the cam disc 177 is theposition in which the end of the cam block 171 is placed on the end ofthe small-diameter region 178 c on the side of the rake region 178 a oris in contact with or adjacent to the stopper surface 178 d. The rakeregion 178 a, the large-diameter region 178 b and the small-diameterregion 178 c face the cam block 171 in this order during rotation of thecam disc 177.

Further, as shown in FIG. 4, the angular range of the small-diameterregion 178 c extends over more than 90° of the perimeter of the cam disc177, in order to utilize this region as a braking region for braking thedriving motor 113 after the second switch is returned to the offposition and the driving motor 113 is de-energized. Specifically, thesmall diameter region 178 c has the braking region.

Further, a safety lever 143 for disabling the depressing operation ofthe trigger 141 is provided on the handgrip 107. The depressingoperation of the trigger 141 is disabled when the safety lever 143 isplaced in a locked position shown by a solid line in FIG. 1, while thedepressing operation is enabled when the safety lever 143 is placed in alock released position shown by a phantom line in FIG. 1. Further, alight 145 (see FIG. 1) for illuminating a pin driving region is providedon the body 101. A light illuminating switch 147 is turned on by thesafety lever 143. When the safety lever 143 is placed in the lockedposition, the switch 147 is turned off so that the light 145 goes out.

Then, an operation of the pin tucker 100 will now be explained withreference to FIGS. 4 to 30, mainly with regard to the operating device160. FIGS. 4, 5 and 22 show the initial state in which the operatingdevice 160 is not yet operated by the user. In the initial stat, theswing arm 164 is in the interlocked position and the end sure 164 a ofthe swing arm 164 faces the engagement portion 171 a of the cam block171 with a predetermined spacing therebetween. Further, the end of thecam block 171 is located at the end of the small-diameter region 178 cof the cam disc 177. Both the first and second switches 148 and 173 arein the off position and the driving motor 113 is at a stop. Further, thedriver 129 is located at the bottom dead center (see FIG. 2).

FIGS. 6, 7 and 23 show the state in which the depressing operation ofthe trigger 141 is started by the user. In this state, the end surface164 a of the swing arm 164 is in surface contact with the engagementportion 171 a of the cam block 171. FIGS. 8, 9 and 24 show the state inwhich the trigger 141 is further depressed and the cam block 171 ispushed by the swing arm 164 moving together with the trigger 141.Specifically, the cam block 171 is moved to a position (contactavoidance position) in which the cam block 171 is disengaged from thestopper surface 178 d of the cam disc 177, so that the cam disc 177 isallowed to rotate. Immediately thereafter, the first and second switches148 and 173 are turned on. Further, the free leg 166 b of the secondtorsion spring 166 on the swing arm 164 passes over the flat surfaceportion 169 a of the guide surface 169. However, the swing arm 164 isheld in the interlocked position against the biasing force of the thirdtorsion spring 167 by the frictional force of the contact surfacesbetween the swing arm 164 and the engagement portion 171 a of the camblock 171.

FIGS. 10, 11 and 25 show the state in which the trigger 141 is furtherdepressed and the first switch 148 is turned on via the lever 163 b andat the same time the second switch 173 is turned on via the cam block171, the push pin 174 and the switch arm 172, so that the driving motor113 is energized. When the driving motor 113 is energized, as mentionedabove, the gears 133, 135 of the hammer drive mechanism 119 are drivenvia the speed reducing mechanism 115 and lifting of the hammer 125starts. Specifically, the driver 129 starts pin driving operation.Further, when the gears 133, 135 are driven, the cam disc 177 startsrotating counterclockwise as viewed in the drawings and moves the camblock 171 in the throwing direction via the rake region 178 a.

FIGS. 12, 13 and 26 show the state in which the trigger 141 is furtherdepressed down to the depressing end and the cam block 171 is flintiermoved in the throwing direction by the rake region 178 a of the can disc177. After the trigger has reached the depressing end, the cam block 171is further moved in the throwing direction by the rake region 178 a ofthe cam disc 177. Thus, the engagement portion 171 a of the cam block171 is disengaged from the end surface 164 a of the swing arm 164, sothat the frictional force between the contact surfaces ceases to exist.As a result, the swing arm 164 is allowed to rotate from the interlockedposition to the interlock released position by the biasing force of thethird torsion spring 167. This state is shown in FIGS. 14, 15 and 27.

The cam disc 177 continues to rotate and the end of the cam block 171goes on the large-diameter portion 178 b of the cam disc 177. Thus, thesecond switch 173 is held in the on position. Further, the first switch148 that has been turned on by depressing the trigger 141 is also heldin the on position. Therefore, the driving motor 113 is also heldrunning This state is shown in FIGS. 16, 17 and 28. The end of the camblock 171 then moves with respect to the large-diameter portion 178 b ofthe cam disc 177 while being held in engagement therewith. In thisprocess, the driver 129 performs a pin driving movement. Specifically,the hammer 125 is moved up to the top dead center via the lift rollers137, 139 of the hammer drive mechanism 119 and the cam 140, and then thehammer 125 is disengaged from the cam 140. The driver 129 then performsa downward driving movement together with the disengaged hammer 125 bythe built-up spring force of the compression coil spring 127. Thus, thedriver 128 drives a pin into the workpiece. After completion of thedriving movement, the hammer 125 is held at the bottom dead center bycontact with the stopper 126.

The cam disc 177 further continues to rotate until the end of the camblock 171 reaches small-diameter region 178 c of the cam disc 177. Whenthe end of the cam block 171 reaches the small-diameter region 178 c,the cam block 171 is moved in a direction opposite to the depressingdirection of the trigger 141 via the switch arm 172 and the push pin 174by the biasing force of the first torsion spring 175. As a result, thesecond switch 173 is returned to the off position and the driving motor113 is de-energized. This state is shown in FIGS. 18, 19 and 29.Thereafter, the driving motor 113 continues to rotate by inertia whilebeing braked and then stops. As a result, the cam disc 177 also rotateand returns to the initial position at the end of the small-diameterregion 178 c. Further, each of the component parts of the hammer drivemechanism 119 also returns to its initial position

When the user releases the trigger 141 to stop the depressing operation,the trigger 141 returns to the pre-operational or released position bythe biasing force of the compression coil spring 165. At this time, whenthe swing arm 164 moves together with the trigger 141, the free leg 166b of the second torsion spring 166 is pushed in contact with theinclined surface portion 169 b of the guide surface 169. Thus, the swingarm 164 moves in an attempt to return to the initial position or theinterlocked position. This state is shown in FIGS. 20, 21 and 30. Atthis time, the swing arm 164 contacts the underside of the engagementportion 171 a of the cam block 171, and the second torsion spring 166 isguided by the inclined surface portion 169 b of the guide surface 169and elastically deforms. By such elastic deformation, the swing arm 164passes in contact with the underside of the engagement portion 171 a andreturns to the initial position or interlocked position shown in FIGS.4, 5 and 22. Further, when the second torsion spring 166 moves as guidedby the inclined surface portion 169 b of the guide surface 169, thesecond torsion spring 166 deforms the third torsion spring 167 andreturns it to the initial position while deforming per se. As a result,the third torsion spring 167 is (additionally) provided with a biasingforce of rotating the swing arm 164 from the interlocked position to theinterlock released position. Thus, one diving operation of driving in apin by the driver 129 is completed.

The user may possibly discontinue the depressing operation of thetrigger 141 halfway through the driving operation of the driver 129, forexample, during the process of lifting the driver 129 from the bottomdead center to the top dead center. At this time, in the operatingdevice 160 of this embodiment, the second switch 173 associated with theinternal switch 161 is held in the on position, but the first switch 148associated wit the trigger switch 163 is returned to the off positionwhen the trigger 141 returns to the released position. Therefore, thedriving motor 113 is de-energized and thus the driving operation can bestopped in progress. Further, after such interruption, when the trigger141 is depressed again to turn on the first switch 148, the drivingmotor 113 is energized. Specifically, the once interrupted drivingoperation of the driver 129 can be resumed without causing a problem.

As described above, in a fist operation mode of the operating device 160according to this embodiment when the trigger 141 is depressed, thefirst switch 148 is turned on, and the second switch 173 is interlockedwith the depressing operation of the trigger 141 to be turned on andheld in the on position. When the trigger 141 is released, the firstswitch 148 is returned to the off position. The first operation modecorresponds to the “first mode” according to this invention.

Further, in a second operation mode, when the depressing operation ofthe trigger 141 is continued, the first switch 148 is held in the onposition, and the second switch 173 is held in the on position for apredetermined period of time in the working stroke and then returned tothe off position. The second operation mode corresponds to the “secondmode” according to this invention. The working stroke of the drivingmember is started when the operating device 160 is put into the firstoperation mode by the depressing operation of the trigger 141. After apredetermined period of time elapses after start of the working stroke,the operating device 160 switches from the first operation mode to thesecond operation mode.

According to the representative embodiment, each time the trigger 141 isdepressed once, the driver 129 is caused to perform one drivingoperation and then stopped. Such movement can be performed only bydepressing the trigger 141. Therefore, compared with the prior art whichrequires an operation of pressing a contact detection arm against aworkpiece and an operation of depressing a trigger, the operability ofthe operating device 160 can be enhanced

Further, in this embodiment, the depressing direction of the trigger 141is the same as the moving direction of the cam block 171. With thisconstruction, the system of interlocking the cam block 171 with thedepressing operation of the trigger 141 can be easily designed. Further,interlocking between the trigger 141 and the cam block 171 and releaseof the interlock is done by the rotatable swing arm 164. To this end,the swing arm 164 is formed by a fit between a shaft and a hole.Therefore, machining accuracy can be readily insured and smooth movementcan be realized. Further, by utilizing the elastic deformation of thesecond torsion spring 166, the swing arm 164 can be efficiently returnedfrom the interlock released position to the interlocked position whilebeing cased to interfere with the cam block 171.

Further, in this embodiment, the cam block 171 turns on the secondswitch 173 by interlocking with the depressing operation of the trigger141. The cam block 171 is controlled by the rotatable cam disc 177, andthe cam disc 177 is rotated together with the gear 133 of the hammerdrive mechanism 119 that drives the hammer 125. Therefore, the time atwhich the cam block 171 turns the second switch 173 on and off can bereadily adjusted with respect to the time at which the hammer drivemechanism 119 drives the hammer 125. Further, the time at which thefirst switch 148 is turned off, or the time at which the driving motor113 is de-energized, can be adjusted in consideration of the positionwhere the driving motor 113 stops after being braked. In thisembodiment, the braking region for braking the driving motor 113 isprovided in the small-diameter region 178 a of the cam disc 177. As aresult, after de-energization of the driving motor 113, the drivingmotor 113 and the hammer drive mechanism 119 can be stopped with arelatively small impact thereupon.

Further, in this embodiment, the trigger 141 and the cam block 171 areinterlocked with each other or such interlock is released by rotation ofthe swing arm 164 between the interlocked position and the interlockreleased position. Alternatively, in place of the swing arm 164, asliding member that linearly moves in a direction crossing thedepressing direction of the trigger 141 may be provided and interlocksthe trigger 141 and the cam block 171 or releases the interlock bymoving between the interlocked position and the interlock releasedposition. Further, in this embodiment, the pin tucker 100 is describedas a representative example of the power tool in the present invention.However, the present invention is not limited to the pin tucker 100, butmay be applied to any power tools of the type which performs the drivingmovement of the hammer 125 by a spring force of the compression coilspring 127.

Further, according to the representative embodiment, the speed reducingmechanism 115 includes a “reverse rotation preventing mechanism” thatprevents reverse rotation in a direction opposite to the direction ofrotation (normal rotation) when the motor 113 is driven. A ratchet wheel116 and a leaf spring 118, which will be described below, form hisreverse rotation preventing mechanism. The reverse rotation preventingmechanism of the speed reducing mechanism 115 is shown in FIGS. 34 and35. FIG. 34 shows the ratchet wheel 116 and the leaf spring 118 formingthe reverse rotation preventing mechanism of the speed reducingmechanism 115 in this embodiment, as viewed from the side of the drivingmechanism 117 in FIG. 3. FIG. 35 is a side view of the ratchet wheel 116and the leaf spring 118 shown in FIG. 34.

As shown in FIGS. 34 and 35, the ratchet wheel 116 has a disc-like shapeand is mounted on the output shaft 115 a of the speed reducing mechanism115. A plurality of engagement grooves 116 a are provided in thecircumferential region (the ratchet face on the outer circumferentialportion) of the ratchet wheel 116. Each of the engagement grooves 116 aincludes a vertical wall 116 b extending horizontally as viewed in FIG.35 and an inclined wall 116 c extending obliquely from the bottom of thevertical wall 1II b. Further, a leaf spring 118 is provided to face theratchet face of the ratchet wheel 116 and is allowed to rotate on theoutput shaft 115 a (corresponding to the “support portion” according tothis invention) with respect to the ratchet wheel 116. The leaf spring118 includes an engagement claw 118 a, a first contact piece 118 b and asecond contact piece 118 c on the outer edge portion. The engagementclaw 118 a is configured to extend along the inclined wall 116 c of theengagement groove 116 a of the ratchet wheel 116 and can press andengage with the engagement groove 116 a In engagement with theengagement groove 116 a, when the driving motor 113 is driven, theengagement claw 118 a allows the ratchet wheel 116 to rotate in thedirection of an arrow 10 in FIG. 34 (in the normal or forward direction)and prevents the ratchet wheel 116 to rotate in the direction of anarrow 12 in FIG. 34 (in the reverse direction).

Specifically, when the ratchet wheel 116 rotates in the normal direction(“rotates in one direction of the ratchet wheel” according to thisinvention), the inclined wall 116 c of each of the engagement grooves116 a slides with respect to the engagement claw 118 a and theengagement claw 118 a comes into engagement with the engagement grooves116 a one after another along the circumferential region of the ratchetwheel 116. Thus, the ratchet wheel 116 is allowed to rotate in thenormal direction. On the other hand, when the ratchet wheel 116 rotatesin the reverse direction (“rotates in the other direction of the ratchetwheel” according to this invention), the engagement claw 118 a buttsagainst the vertical wall 116 b of any predetermined one of theengagement grooves 116 a. Thus, the engagement claw 118 a is locked inthe engagement groove 116 a and held in the locked state. As a result,the ratchet wheel 116 is prevented from rotating in the reversedirection. The leaf spring 118 is a feature that corresponds to the“claw member” according to this invention.

In the construction shown in FIG. 34, the center of rotation of the leafspring 118 coincides with the center of rotation of the ratchet wheel116. In this invention, however, the centers of rotation of the leafspring 118 and the ratchet wheel 116 may coincide with each other or maybe displaced from each other. Further, in the construction shown in FIG.34, the plurality of the engagement grooves 116 a are provided in thecircumferential region of the ratchet wheel 116. In this invention,however, engagement grooves corresponding to the engagement grooves 116a may be provided on the outer peripheral portion of the ratchet wheel116 having a circular arc surface, and a member having an engagementclaw adapted to the engagement grooves may be used in place of the leafspring 118.

When the driving motor 113 is driven and the ratchet wheel 116 rotateson the output shaft 115 a in the normal direction, the leaf spring 118may be dragged by the ratchet wheel 116 in the same direction androtated with rotation of the ratchet wheel 116 by the frictional forcebetween the engagement claw 118 a and the engagement grooves 116 a (theinclined wall 116 c) held in engagement with each other. Therefore, inthis embodiment, the leaf spring 118 is configured to have the firstcontact piece 118 b that can contact a fist contact wall 105 a of thegear housing 105. With this construction, the leaf spring 118 rotates onthe output shaft 115 a in the direction of the arrow 10 in FIG. 34 untilthe first contact piece 118 b contacts the first contact wall 105 a in afirst stop position (shown by a solid line in FIG. 34). Thus, furthernormal rotation of the leaf spring 118 is prevented in the fist stopposition. The first stop position, the first contact piece 118 b and thefirst contact wall 105 a are features that correspond to the “firstposition”, the “first contact portion” and the “first contactedportion”, respectively, according to this invention.

When the ratchet wheel 116 rotates in the reverse direction and the leafspring 118 rotates in the same direction as the ratchet wheel 116 by theforce of engagement between the engagement claw 118 a and the engagementgrooves 116 a, the second contact piece 118 c contacts a second contactwall 105 b of the gear housing 105 in a second stop position (shown by aphantom line in FIG. 34). Thus, further reverse rotation of the leafspring 118 is prevented in the second stop position. The second stopposition, the second contact piece 115 c and the second contact wall 105b arm features that correspond to the “second position”, the “secondcontact portion” and the “second contacted portion”, respectively,according to this invention.

In other words, the leaf spring 118 is allowed to rotate with apredetermined amount of play (a clearance 106 (d1) in FIG. 34) betweenthe first stop position in which the first contact piece 118 b contactsthe first contact wall 105 a and the second stop position in which thesecond contact piece 118 c contacts the second contact wall 105 b.Therefore, although the ratchet wheel 116 is prevented from rotatingwith respect to the leaf spring 118 in the direction of the arrow 12,the leaf spring 118 itself is allowed to rotate in the reverse directionfrom the second stop position to the first stop position, which resultsin the ratchet wheel 116 being allowed to rotate in the reversedirection together with the leaf spring 118.

An operation of the reverse rotation preventing mechanism of the speedreducing mechanism 115 will now be explained with reference to FIGS. 37and 38. FIG. 37 shows the reverse rotation preventing mechanism in thestate in which the end 171 a of the cam block 171 is butted against thestopper surface 178 d of the cam disc 177 after completion of theworking stroke of the driving operation. FIG. 38 shows the reverserotation preventing mechanism in the state in which the end 171 a of thecam block 171 is disengaged from the stopper surface 178 d of the camdisc 177.

As shown in FIG. 37, immediately after completion of the working strokeof the driving operation, the cam disc 177 is acted upon by inertialforce in the normal direction (in the direction of the arrow 30 in FIG.37). Thus, the end 171 a of the cam block 171 is in contact with thestopper surface 178 d of the can disc 177. The inertial force upon thecam disc 177 is transmitted as a rotating force of the output shaft 115a in the direction of the arrow 10, a rotating force of the lower gear135 in the direction of the arrow 20 and a rotating force of the uppergear 133 in the direction of the arrow 30, in this order from thedriving motor 113 side. Further, immediately after completion of theworking stroke of the driving operation, the engagement claw 118 a ofthe leaf spring 118 is in engagement with the engagement groove 116 a ofthe ratchet wheel 116, and the first contact piece 118 b is in contactwith the first contact wall 105 a of the gear housing 105. Thus, theleaf spring 118 is prevented from being dragged by the ratchet wheel 116in the same direction and rotated with rotation of the ratchet wheel116.

When the end 171 a of the cam block 171 is in contact with the stoppersurface 178 d of the cam disc 177 and also the leaf spring 118 is inengagement with the ratchet wheel 116, the cam block 171 may conceivablybe locked. In such a locked state, even if the trigger 141 is depressed,the end 171 a of the cam block 171 cannot be disengaged from the stoppersurface 178 d, so that the cam block 171 cannot be raised.

Therefore, in this embodiment, even in the state in which the end 171 aof the cam block 171 is in contact with the stopper surface 178 d of thecam disc 177 and also the leaf spring 118 is in engagement with theratchet wheel 116, a predetermined amount of reverse rotation of theratchet wheel 116 and the leaf spring 118 in engagement with each otheris allowed. Specifically, as described above, the leaf spring 118 isallowed to rotate with a predetermined amount of play (the clearance 106(d1) in FIG. 37) between the first stop position in which the firstcontact piece 118 b contacts the first contact wall 105 a and the secondstop position in which the second contact piece 118 c contacts thesecond contact wall 105 b. At this time, the biasing force of thecompression coil spring 127 acts upon the ratchet wheel 116 via thespeed reducing mechanism 115 in a direction to rotate the ratchet wheel116 in the reverse direction. Therefore, the ratchet wheel 116 actedupon by the biasing force of the compression coil spring 127 rotates inthe reverse direction by a distance corresponding to the amount d1 ofthe clearance 106, together with the leaf spring 118 with the engagementclaw 118 a in engagement with the associated engagement groove 116 a.When the leaf spring 118 rotates on the output shaft 115 a in thedirection of the arrow 12 in FIG. 38 and reaches the second stopposition, the second contact piece 118 c contacts the second contactwall 105 b. Thus, further reverse rotation is prevented.

The construction in which the leaf spring 118 can rotate between thefirst stop position and the second stop position, the construction inwhich the first contact piece 115 b of the leaf spring 118 contacts thefirst contact wall 105 a in the first stop position, and theconstruction in which the second contact piece 118 c of the leaf spring118 contacts the second contact wall 105 b in the second stop positionform the “release mechanism” according to this invention.

In the process in which the ratchet wheel 116 rotates together with theleaf spring 118 in the reverse direction by a distance corresponding tothe amount d1 of the clearance 106, the cam disc 177 also rotates in thereverse direction. Thus, as shown in FIG. 38, the end 171 a of the camblock 171 is displaced a predetermined (by an amount of the clearance179) away from the stopper surface 178 d of the cam disc 177 and held inthe contact release state in which the cam block 171 and the cam disc177 are disengaged from each other. Specifically, when the clearance 106between the second contact piece 118 c of the leaf spring 118 and thesecond contact wall 105 b is gone, the clearance 179 (d2) is createdbetween the end 171 a of the cam block 171 and the stopper surface 178 dof the cam disc 177. In this embodiment, the clearance 106 between thesecond contact piece 118 c of the leaf spring 118 and the second contactwall 105 b defines the amount of reverse rotation of the cam disc 177.

The rotating force of this reverse rotation of the cam disc 177 istransmitted to the compression coil spring 127, the upper engagementprojection 125 a of the hammer 125 and the shaft 137 a of the upper liftroller 137 in this order. With the clearance 179 (d2) created betweenthe end 171 a of the cam block 171 and the stopper surface 178 d of thecam disc 177, contact in engagement between the cam block 171 and thestopper surface 178 d can be avoided and the cam block 171 is preventedfrom being locked. As a result, the depressing operation of the trigger141 can be smoothly performed.

DESCRIPTION OF NUMERALS

100 pin tucker (power tool)

101 body

103 motor housing

105 gear housing

105 a first contact wall

105 b second contact wall

106 clearance

107 handgrip

109 battery case

111 magazine

112 injection part

112 a pin injection post

113 driving motor (motor)

115 speed reducing mechanism

115 a output shaft

115 b driving gear

116 ratchet wheel

116 a engagement groove

116 b vertical wall

116 c inclined wall

117 driving mechanism

118 leaf spring

118 a engagement claw

118 b first contact piece

118 c second contact piece

119 hammer drive mechanism (operating mechanism)

121 slide guide

123 slider

125 hammer

125 a upper engagement projection

125 b lower engagement projection

126 stopper

127 compression coil spring

129 driver (driving member)

131 connecting pin

133 upper gear

133 a shaft

134 frame

135 lower gear

135 a shaft

137 upper lift roller

137 a support shaft

139 lower lift roller

139 a support shaft

140 cam

141 trigger

143 safety lever

145 light

147 light illuminating switch

148 first switch

160 operating device

161 internal switch

163 trigger switch

163 a shaft

163 b lever

164 swing arm (interlocking member)

164 a end surface

165 compression coil spring

166 second torsion spring (elastic member, second spring member)

166 a one leg

166 b other (free) leg

167 third torsion spring (first spring member)

167 a one leg

167 b other (free)leg

168 guide plate (guide member)

169 guide surface

169 a flat surface portion

169 b inclined surface portion

171 cam block

171 a engagement portion

172 switch arm

172 a shaft

173 second switch

174 push pin

174 a biasing spring

175 first torsion spring

177 cam disc (control member)

178 cam face

178 a rake region (interlock released region)

178 b large-diameter region (on-state continuation region)

178 c small-diameter region (off-state return region)

178 d stopper surface

179 clearance

1. A power tool comprising: a body having a motor housing, a handgrip,and a gear housing, the gear housing having a driving member and ahammer drive member, the hammer drive member having an upper gear and alower gear positioned within the gear housing so as to be rotatable inopposing directions on a longitudinal axis wherein one working strokecomprises one rotation of the upper gear and the lower gear; a motordisposed in the motor housing; a trigger; an interlocking member; ahammer having an upper and a lower engagement projection; a compressioncoil spring; an operating device having a first mode, a second mode, atrigger switch biased into an off position, and an internal switchbiased into an off position, the trigger switch and the internal switchoperatively connected for completing one working stroke after finishingthe first mode and the second mode, the first mode comprising theinternal switch moving to an on position by interlocking with thetrigger switch while the trigger switch is in an on position, thetrigger switch being activated to the on position in response to alinear depression applied to the trigger, thereby energizing the motorfor a predetermined period of time as the first mode, beforede-energizing the motor after the predetermined period of time asbeginning the second mode, the second mode comprising the internalswitch releasing its interlocking position with the trigger switch andreturning to the off position in response to the predetermined period oftime ending, and the trigger switch remaining in the on position duringthe second mode; a cam block provided in the internal switch adapted tolinearly move with depressing operation of the trigger; and a switch armprovided in the internal switch rotatably adapted for rotation by thecam block, biased by a first torsion spring.
 2. The power tool asdefined in claim 1, wherein: the trigger switch further comprises afinger operating member for depressing in the operating direction and aninterlocking member operatively connected to the finger operating memberhaving an operating position and a non-operating position, wherein thetrigger switch is interlocked with the internal switch as the operatingposition and interlock releases to comprise the non-operating position,wherein the interlocking member, normally biased into a non-operatingposition, is provided with a swing arm being movable in response to abiasing force, the interlocking member adapted to be held in theoperating position against a biasing force by contact with the internalswitch in the first mode, and further adapted to be switched from theoperating position to the non-operating position, thereby releasingcontact with the internal switch in response to the internal switchfurther moved in a trigger depressing direction in a manner such thatthe interlocking member is switched from the operating position to thenon-operating position and released from the interlock with the internalswitch.
 3. The power tool as defined in claim 2 further comprising aguide member for guiding the interlocking member to be switched from thenon-operating position to the operating position in response to thefinger operating member returning to a pre-operational position byrelease of the depressing operation of the finger operating member, asecond torsion spring provided on the swing ARM wherein at completion ofthe second mode, the interlocking member is guided by a guide memberfrom the non-operating position to the operating position in response torelease of the depressing operation of the finger operating member. 4.The power tool as defined in claim 3 further comprising a first springmember biasing the interlocking member into the non-operating positionand a second spring member defined by the second torsion spring, thefirst and second spring members configured with each other such that therespective biasing forces act upon each other, wherein, when theinterlocking member is switched from the operating position to thenon-operating position in response to a biasing force of the firstspring member, the second spring member transmits the biasing force ofthe first spring member to the interlocking member as a force of movingthe interlocking member from the operating position to the non-operatingposition, and when the interlocking member is switched from thenon-operating position to the operating position, the first springmember is returned to an initial position by the second spring memberguided by the guide member.
 5. The power tool as defined in claim 2,wherein the interlocking member is configured for rotation in adirection crossing the depressing direction of the finger operatingmember.
 6. The power tool as defined in claim 5, further comprising theinterlocking member being rotatably configured in such a manner to havesurface contact the internal switch in the depressing direction inresponse to depression of the finger operating member, in the operatingposition in response to frictional force of the surface contact, androtate to the non-operating position in response to biasing force of thesecond torsion spring when the interlocking member is disengaged fromthe internal switch and the frictional force ceases to exist.
 7. Thepower tool as defined in claim 5, further comprising the interlockingmember being slidable in respect to the internal switch in response tomovement of the finger operating member in a direction opposite to thedepressing direction of the finger operating member.
 8. The power toolas defined in claim 1, the internal switch further comprising anoperating member defined by the cam block and a control member definedby a cam disc, the operating member being movable in a throwingdirection in response to the internal switch moved to the on positionand the control member being moveable in response to the motor andconfigured to control movement of the operating member switching betweenthe first mode and the second mode, the control member furthercomprising: an interlock release releasing the interlock between theoperating member and the trigger switch while holding the internalswitch in the on position, an on-state continuation region adjacent tothe interlock release for holding the internal switch in the on positionafter release of the interlock, and an off-state return region adjacentto the on-state continuation region for allowing the operating member tomove in a direction opposite to the throwing direction by disengagementfrom the operating member.
 9. The power tool as defined in claim 8,further comprising a braking region provided in the off-state returnregion for enabling the motor to be braked after the motor isde-energized.
 10. The power tool as defined in claim 1 furthercomprising: a drive device for driving the coil spring in a windingdirection against the spring force of the coil spring, a rotatingelement configured for rotation in a normal direction against the springforce of the coil spring having a locked part and a driving standbyposition, a locking member contacting the locked part of the rotatingelement for locking the rotating element in a driving standby positionin response to drive means winding and driving the coil spring, andfurther locking the rotating element in the driving standby position inresponse to the rotating element rotating one turn in the normaldirection after releasing the lock, a reverse rotation preventingmechanism adapted for allowing the rotating element to rotate in thenormal direction and preventing the rotating element from rotating in areverse direction, and a release mechanism adapted for allowing apredetermined amount of reverse rotation of the rotating element by thereverse rotation preventing mechanism, avoiding contact in engagementbetween the locked part of the rotating element and the locking member,when driving of the drive means is stopped and the rotating element islocked in the driving standby position via the locking member.
 11. Thepower tool as defined in claim 10, wherein: the reverse rotationpreventing mechanism further comprises a claw member having anengagement claw, a first contact portion, a second contact portion, afirst position, a second position, and a ratchet wheel, the ratchetwheel having a plurality of engagement grooves provided in itscircumferential region, configured to engage with the engagement claw,and adapted to be rotatable through interlocking with the rotatingelement, wherein as first position in response to the ratchet wheelrotating in one direction, the engagement claw engages with theengagement grooves along the circumferential region of the ratchetwheel, in a manner such that the rotating element is able to rotate inthe normal direction, and in response to the ratchet wheel rotating in asecond direction, the engagement claw locks in one engagement groove, ina manner to prevent the rotating element from rotation in the reversedirection, and wherein as the second position in response to the ratchetwheel rotating in the one direction, the release mechanism continues toallow the normal rotation of the rotating element by the reverserotation preventing mechanism, and in response to the ratchet wheelrotating in opposite direction, the engagement claw engages with thepredetermined engagement groove while rotating in the other directiontogether with the ratchet wheel, in a manner to allow the releasemechanism a predetermined amount of reverse rotation of the rotatingelement.
 12. The driving power tool as defined in claim 11, the releasemechanism further comprising a support portion rotatably provided tosupport the claw member between the first position and the secondposition, a first contacted portion configured to contact the firstcontact portion of the claw member in the first position, and a secondcontacted portion configured to contact the second contact portion ofthe claw member in the second position, wherein the release mechanism isarranged in such a manner that in response to the ratchet wheel rotatingin one direction, the release mechanism continually allows normalrotation of the rotating element by the reverse rotation preventingmechanism, placing the claw member in the first position and the firstcontact portion in contact with the first contacted portion, therebycreating a predetermined clearance between the second contact portionand the second contacted portion, and wherein the release mechanism isarranged in such a manner that in response to the ratchet wheel rotatingin an opposite direction, the engagement claw engages with thepredetermined engagement groove while rotating in the opposite directionwith the ratchet wheel, the release mechanism further allowing apredetermined amount of reverse rotation of the rotating element, theclaw member rotating from the first position to the second position bythe predetermined clearance and the second contact portion contactingthe second contacted portion, defining the amount of reverse rotation ofthe rotating element.
 13. The power tool as defined in claim 1 whereinthe tool is a pin tucker or a nailing machine.